Mammalian Ovarian folliculogenesis is a precise series of developmental events that requires the cooperative efforts of several cell types and the integration of acomplex set of chemical messages that ultimately lead to successful matuation and ovulation of the oocyte. Within the past few decades, the individual steps in many of the essential metabolic pathways within the ovary have been elucidated. However, in contrast little is known concerning the homeostatic mechanisms by which the follicular compartment regulates and coordinates metabolic and physiological processes in the face of a constantly changing internal micro and external macro environment. Clearly a thorough understanding of the regulatory mechanisms involved in the events that promote follicular differentiation would be of great importance for our comprehension of basic reproductive processes and more generally basic cellular processes. Thus, the overall objective of this proposal is to examine fundamental aspects of the hormonal mechanisms responsible for folliculogenesis. Special attention will be given to: 1) the organization of the cytoskeleton in granulosa cells in vivo and the relationship of this organization to the functional state of the follicle 2) the acute effects of FSH, estradiol and androstenedion on cytoskeletal architecture 3) the role of each component of the cytoskeleton in mediating cellular responses to FSH 4) the relationship of the cytoskeleton to metabolic pathways responsible for estrogen biosynthesis, Ca+2 and cAMP metabolism. The proposed experiments will utilize both in vivo and in vitro model systems to evaluate the effects of hormones on the cytoskeleton as judged by conventional TEM, whole mount 100KV EM, a new rotary shadow replica technique and immunofluorescent methodologies. Corraborative evidence related to the role of the cytoskeleton in FSH stimulation will be obtained through the use of various cytoskeletal perturbants and metabolic inhibitors. My goal is to relate cytoarchitectural modification in granulosa cell structure induced by FSH to physiological parameters related to hormone stimulation. A full understanding of the varied aspects of ovarian activity cannot be gained until the factors governing cellular activities are clarified.